1978 Johnson 115 hp Backfires on idle and at high revs.

[cjhols]

Hi all.
Bit of a newbie so bare with me. I bought this old boat that hadn't been started for 18months but supposedly ran well. Anyway the only way I can get it started is to use "Starter Spray". The only problem is that it backfires at idle and is really bad at high revs. There is a sweet spot just past idle where it seems to run fine??? I checked the spark plugs and they seemed to look ok but had a small amount of oil on them. Particularly on cylinder 1. Any help would be grateful,
Peter

 

[emdsapmgr]

Check to see that all the spark plug wires are going to the correct spark plugs. That includes the wires going from the power packs to the coils.

 

[cjhols]

That's a reasonable idea but you can't really get these around the wrong way as they are "D" connectors. I haven't (don't know how) to check the connections from the Power Packs.????
Thanks again I am new to this so I appreciate all the help I am getting.
Peter

 

[racerone]

Having to use starter spray indicates there is something wrong.--------And have you checked compression on this motor ?

 

[Barnacle_Bill]

I would rebuild the carbs. They can gum up inside from sitting that long without being ran.

 

[cjhols]

Eureka the guy I bought it off had the spark plug connections around the wrong way. This must have been past the coils as the plugs now have to cross. Anyway she is a goer. Thanks for all your help.
Peter